This way, we don't need to distribute liberrhand header files

We were trying to install libbpmclient headers. This was obviously
a typo.

This is needed as libclient uses libhutils explicitly now

The only place we need them is in revision.c. So, we have moved
them there.

They should be only accessible through our API in
include/revision.h

Instead, we are now using the version.sh script to do that

Without this, clang issues an error.

Some errors were not in the error descriptor table and some
were missing entirely.

Without this, clang issues an error.

This allows us to set, for instance, CC to 'gcc' or 'clang'.

DEVIO filenames are not standard for all DEVIO types.

This fixes #99 github issue.

This is nedded as some older compiler versions (e.g., GCC <= 4.6.3)
complain about the way we initialize empty structures.