Expand cmake documentation

Collected small changes and bugfixes for next patch release

Added boxrel example and simplified latte.in

cmake: implicit fortran libs need to linked last

add more thorough checks on parsing reaxff force field and signal when the lgvdw setting is correct.

closes #876

Limit atom energy change in fix dt/reset

Add support for inline format strings to immediate variable substitution

Variable style 'string' substitutes variables in definition

Apply modifications to MEAM & MEAM/C as found by Kyung-Han Kang

Improve fix manifoldforce warning

Add code coverage target to CMake

Bond/react update

Fix the tail correction with pair_nm

Collected bugfixes and updates

cmake: add DOWNLOAD_MSCG option

rebase