Add apt-get update, su -c, GT.M x86_64 shared lib support

For cloud installs apt-get update needs to be ran before we install git,
build-essentials, etc.

Move most file creation and program execution to run su foia -c so the
commands are ran with the instance user and not as root

Add GT.M shared libary support for x86_64 as by default gtminstall will
only install the shared library version and not have the programs in
$gtm_dist

Add platform environment variable for cmake build name generation

Change-Id: Ide4aaa433eace00bdcccfbfc7fe03493069f91eb
Fix hardcoding of vagrant username

Racksapce and other cloud providers don't use a vagrant username, which
will cause the autoInstaller script to throw errors and not perform the
intended actions.

Change-Id: Ie9d0aaaa1b4aa04b3a85c8662b2e27c2cc9ac5f4
OSEHRA-Id: http://issues.osehra.org/browse/VAF-147