Flag that lists functions to inline

[fortunac]

Currently, the inline flag (--wp-inline) will inline all of the function calls. We should have a flag that lists which functions we want to inline, ex: --wp-inline-funcs=food,bar,baz.

When the inline flag is set, the wp plugin creates an inline_env which passes in spec_inline as the default function spec: https://github.com/draperlaboratory/cbat_tools/blob/master/wp/lib/bap_wp/src/precondition.ml#L464-L475

When the environment is created, it initializes a handler for each sub in the program. If the subroutine doesn't match the prerequisites for spec_verifier_error, spec_verifier_assume, or spec_verifier_nondet, it will be mapped to spec_inline as seen in https://github.com/draperlaboratory/cbat_tools/blob/master/wp/lib/bap_wp/src/environment.ml#L114-L122

At this point, we can specify exactly which functions we want to be inlined and map other specs to the remaining functions.

BAP flags can be set in the wp.ml plugin file: https://github.com/draperlaboratory/cbat_tools/blob/master/wp/plugin/wp.ml#L142-L161

[fortunac]

Handled in #64