Error handling mechanism updated, with some other updates

* Error handling mechanism refined:

  * Removed inline error type

  * OOM error object is now static allocated

  * Error descriptions are described in one place (rose/error_desc.inc) and inserted to proper places via macros

* White space formatting

* Changed default compilers to gcc/g++

* Fixed warnings under gcc/g++

* Renamed r_run to r_eval, added r_eval_from_port

* Used static RTypeInfo instances to to simplify RState initialization process

* Keyword symbols are now direct RState struct fields

* All r_cons call are ensure'd