Fix for icx

This is a patch release of g5pert with fixes for using icx. Essentially a Fortran flag was being applied to C code, and icx threw an error.

This also adds some boilerplate Markdown compared to v1.1.2.

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What's Changed

• Updates from rt-GEOSadas-5_27_1p2_toGit-2 comparison on 2021-Feb-02. by @mathomp4 in #6
• Bugfixes for icx by @mathomp4 in #7

Full Changelog: v1.1.1...v1.1.3