Added TNG source and header (no tests). They are compiled into libgromacs.so.

Change-Id: Idb636218d012a73eb7f43b64420d1e4b80e6046f
Added TNG output option to mdrun.

Change-Id: I286eba730019206c285ebe82fa637d86398606e6
Fixed indentation in last commit

Change-Id: Iacd2024676737e91ead2b4bae9e8e6988ba66877
Add TNG compression option to mdrun

Change-Id: I67bd50bde05c632bdeaf4cacee88153ac4a602c7
Pass tng compression option to mdrunner

Change-Id: I97ef023f7bb74090fc805d921166d623db17777e
Moved tng header file to legacyheaders.

Change-Id: Ifebbde7860c7d8898e350a83b526aaa436c973aa
Updated tng_io.c and tng_io.h to current version, to avoid name conflicts

Change-Id: I517af209d4402a22de4f41d326e2affb0267fe2c
First steps towards opening a tng file along with other output files.

Change-Id: Ie5559aac7c34f400f71e0193b426afc264329c3a
Destroy TNG struct when finished. Write some molecule info to TNG file (no chain, residues or atoms yet).

Change-Id: I5a187c1ca39ce726de1c9c1a6fb8ca98a058162e