There are cases where it is useful to return to geographic
coordinates from cartesian.  One example is when you have a
mobile node, the position is updated in cartesian coordinates
but you may have a need to understand the geographic position
or heading when determining position relative to other objects
placed geographically, or to compute compass heading or surface
speed.

- Added documentation to raw-text-config.h
- Fixed abort conditions in raw-text-config.cc, RawTextConfigLoad::Strip
- Fixed formatting of ParseLine block in load functions
- Added value.clear() after setting attribute
- Added --load option to config-store-save example, removed config-store-load
- Updated comments, doxygen docs, and example help text.

-- Added GPL license to config-store-load.cc example
-- Enclosed all if-condition code in braces
-- Changed ASSERT checks on inputs in raw-text-config.cc to ABORT checks

There were a number of constructive comments on the original
merge request.

1.  Prior checks in RawTextConfigLoad::Strip ensured the value string
was entirely enclosed in quotation marks.  The original MR removed
those checks.  This revision reintroduces those checks.  Assert
messages have been improved with more information.
2.  RawTextConfigLoad::ParseString was not checking for an empty
line before accessing the first element.
3.  RawTextConfigLoad::ParseString was improved to better handle
whitespace prior to the final value field.

A new config-store-load example was created to allow one to check
a hand-edited config-store raw text file to test the new features.

Features include: ignore # (hash) prefixed comment lines,
ignore blank lines, allow multi-line values.  The latter
feature is particularly useful for entering large arrays
of values that may be set to a container structure.

Both PairChecker and AttributeContainerChecker factory functions
modified to return more generic AttributeCheckers similar to other
attribute types. By removing the templated return type, the internal
templated classes become necessary to define checkers for each
templated type. This follows the pattern in PointerChecker and
ObjectContainerChecker.

The pair-value-test-suite and attribute-container-test-suite were
amended to account for the changes in the checker factories. All
tests continue to pass.

Plenty of documentation was added to PairValue and AttributeContainerValue
and I also removed some dead code.

- Removed unnecessary files src/core/model/{attribute-container,pair}.cc
- Removed 'explicit' modifier to PairChecker
- Modified output stream operator for PairValue; update PairValueTestCase
- Updated src/core/wscript to latest master
- Added Pair and AttributeContainer to utils/print-introspected-doxygen.cc

This file should be part of another merge request.

This commit adds the ability to read / write attributes corresponding
to STL containers or pair structures.  Testcases are included and
demonstrate how to add container or pair member variables as
attributes to your class.

* Handle code review comments (due to Rediet and Mohit)
* Add attribute to configure netmap sync and notify period

This commit:
	- Add DPDK emulation support in fd-emu examples
	- Minor DpdkNetDevice Documentation Changes
Co-authored-by: Hrishikesh Hiraskar <hrishihiraskar@gmail.com>
Co-authored-by: Mohit P. Tahiliani <tahiliani@nitk.edu.in>

Co-authored-by: Hrishikesh Hiraskar <hrishihiraskar@gmail.com>
Co-authored-by: Mohit P. Tahiliani <tahiliani@nitk.edu.in>

Co-authored-by: Harsh Patel <thadodaharsh10@gmail.com>
Co-authored-by: Mohit P. Tahiliani <tahiliani@nitk.edu.in>

Co-authored-by: Hrishikesh Hiraskar <hrishihiraskar@gmail.com>
Co-authored-by: Mohit P. Tahiliani <tahiliani@nitk.edu.in>

Co-authored-by: Harsh Patel <thadodaharsh10@gmail.com>
Co-authored-by: Mohit P. Tahiliani <tahiliani@nitk.edu.in>

Examples added:
	* fd-dpdk-emu-ping : Ping application
	* fd-dpdk-emu-onoff : OnOff application
Co-authored-by: Harsh Patel <thadodaharsh10@gmail.com>
Co-authored-by: Mohit P. Tahiliani <tahiliani@nitk.edu.in>

Extended fd-net-device to support DPDK.
Changes done:
    * Add DpdkNetDevice
    * FdNetDevice modified to support inheritance
    * FdNetDevice modified to support TypeId
    * EmuFdNetDevice modified to initialize DpdkNetDevice
Co-authored-by: Harsh Patel <thadodaharsh10@gmail.com>
Co-authored-by: Mohit P. Tahiliani <tahiliani@nitk.edu.in>

EditorConfig is an universal editor configuration file.

It is not sufficient to configure C++ code style, but enough to set indentation settings in many editors.

See https://editorconfig.org for details.

see merge request !412