Adds infrastructure code for HMAC #25.

Adds command line interface to route code to HMAC.
Adds HMAC mac mode encoding structure.
Adds perform_hmac function
Adds serialize_hmac_mode function.
Adds new command to get a specified number of bytes - Dave Taht #31
Remove extraneous message
Get a minimum of 32 bytes
Tidying
Can return less than 32 bytes
*2 no longer needed
Adds coverity link.
Adds projectile project file.
Reverts to gnu coding style to be consistent with rest of project.
Fixes errors found by coverity scan. Resolves #8.
Merges get-random bytes into the random command.

Adds the -B option to the random command so that there is only one
random command from the cli.
Updates contributing authors.
Updates documentation.
Merge branch 'hmac' into next

Adds skeleton for hmac command.
Adds HMAC command. Resolves #25.
Adds documentation for HMAC command. #25.
Updates tests for new features.
Updates online help.
Bumps version.