Updated README.rst to reflect the build changes.
Updated README.rst to reflect the build changes.

drwells/pyFFTW,hgomersall/pyFFTW,drwells/pyFFTW,hgomersall/pyFFTW,jonathanessen/pyFFTW,jonathanessen/pyFFTW,jonathanessen/pyFFTW,simudream/pyFFTW,drwells/pyFFTW,simudream/pyFFTW,drwells/pyFFTW,frederikhermans/pyfftw-arm,simudream/pyFFTW,frederikhermans/pyfftw-arm,simudream/pyFFTW,hgomersall/pyFFTW