#355 Throw error when basis_get_source_language called without arguments.
#356 Throw error when basis_add_executable called without (existing) source file argument.
#309 Use STREQUAL instead of MATCHES to avoid error with target names that include special characters such as ++.
Merge remote-tracking branch 'github/bugfix/#309-basis_target_link_libraries-target-name-with-++-suffix' into develop
Revert "#309 replace “++” in quick start c++ target name with “pp” and reword as appropriate."

This reverts commit 330ee7e44fcf486a46b0f2dea7cfa6c36f835e28.
Merge remote-tracking branch 'github/develop' into feature/#354-make-install-rpath-optional