Rel9 3 stable spiff pred eval

This PR incorporates the usage of SCF and SRM within Postgres 9.3.
Specifically, a query spiff that evaluates predicates is installed as a static implementation without data.

Code structure-wise, I added a directory namely ```spiff``` to be under both ```src/backend``` and ```src/include```. The former contains all the definitions of the spiff patterns and the associated creation and instantiation functions. The latter contains the headers that declares these functions. In addition, the newly added header directory contains a ```query_spiff_design.h``` file, which defines data structures utilized by query spiffs.

The ```configure``` script is changed to allow an additional flag, namely ```USE_SRM```, which is turned on by ```--with-srm```. Note that this isn't the best name so we probably will change it later. By specifying ```--with-srm```, a few needed compilation arguments, such as ```-std=c99``` and linking arguments, including ```-ldl -ludis86 -lsre /usr/local/lib/libsrm.a -lrt``` are added.

Note also that this branch now requires that udis86, sre, and srm to be installed first.