Ignore result of mlock

Current Linux versions have too low memlock default limits.
Silently ignore mlock result.

• Bump version to 1.0
• return result of ftruncate
• Ignore when the index cannot be memlocked.
• Include libgen.h as per C99

License upgrade from by-sa 3.0 to 4.0

Switch from Creative Commons license "Attribution-ShareAlike 4.0" (by-sa) from version 3.0 to 4.0.
This software is always meant to be compatible to GPL.

Soedinglab compatibility

Can replace the soedinglab fork in hhsuite builds.

0.9.9.7

Thanks @tillea in #2 for reminding me to release tag on github.