GitLab

DOCUMENTATION.md file added to root GPSTk folder for instructions on how to build Doxygen API documentations and LaTex Users Manual.

Added Python documentation to source tree.  Additional tweaks to other documentation in preparation for RC2.6.

GPSTk documentation, updates to README and addition of full GPL/LGPL licensing files needed. LGPL depends on the GPL, so we need to distribute copies of both with the source code.

Updated top-level project README for clarity, including a table of contents, more explicit references to other documentation files within the source file tree, and references to the python bindings package.

Tidied some class member-initializations to avoid #pragma clang diagnostic push.
Removed selected unused variables to avoid "#pragma unused".
(Many warnings remain.)

updates to the docs including additional website information, info about new lib directory, and update of
the build instructions