doc: remove Fortran standards

It has been agreed that Fortran style and guidance is not an FCM
concern. Contents relevant to the build system are moved to the user
guide of FCM Make.
fcm make: inherited build: fix non-failure

Recipe to repeat bug:
* Inherit a build.
* Override with 2 independent Fortran source files containing modules.
* Both files cause build failure. (E.g. due to syntax error.)
* Run fcm make once, 1st source file fails.
* Fix 1st source file.
* Run fcm make again. Should fail, but doesn't.

This change fixes the problem.
Merge pull request #111 from matthewrmshin/fix-build-2-bad-mod-over-inherit

fcm make: inherited build: fix non-failure
Update CHANGES.md
Merge pull request #106 from matthewrmshin/doc-fortran

doc: remove Fortran standards