Fix uploading Doxygen documentation to GH pages from Travis CI

Instead of fiddling with the non-working GIT_ASKPASS/core.askpass
setup, simply store the required Git credentials directly in
~/.git-credentials, which is used by Git's "store" credential helper.

Works on https://travis-ci.org/pah/rapidjson.

Avoids messing with global config when running the script
manually on a developer machine.

This reverts commit 62250923.

This reverts commit 025c516f.

Improve exception safety and add support for swtiching error handling to exceptions

Conflicts:
	include/rapidjson/reader.h

Fixes #59 by adding bool return value for each event handler function

Also modify premake to add all projects in example folder.

This reverts commit ded7dc72.

This reverts commit fd9bc121.

GenericValue::operator= : fixup assignment operator (again)

travis-ci.org: improve config, debug GH_TOKEN issue

 * unconditionally store error state of reader after parsing
 * clear stack after parsing by using a ClearStackOnExit scope guard