Add isegHAL headers n libs

[bhill-slac]

Adds the headers and libs from isegHAL so developers don't need to build it.

[ffeldbauer]

I would not like to copy those files into this package. This way you always have to modify this package, when isegHal is updated. Even if there is no API change, which means you do not need to modify anything else in this package.

The way I solve this problem is, by defining ISEGHAL in the configure/RELEASE file. The Makefile uses it to create USR_INCLUDE and USR_LDFLAGS for compiling. Just copy the lib and headers from isegHal where ever you want and set the path in configure/RELEASE.
You can simply copy the latest version from the CC24 controller directly to your build server, so you do not need to build them yourself.