Add ELong to the set of builtin types

The ELong is required to represent 64-bit quantities in languages
like Java, and also in Ruby when running on a 32-bit architecture.
Merge pull request #4 from thallgren/feature/long-type

Add ELong to the set of builtin types
Merge branch 'master' of https://github.com/mthiede/rgen into nav_comp_inst_extensions