adapted energy parameter fix from ViennaRNA

• fixing a bug with latest gcc version regarding definition of openParen and closeParen pre-definitions leading to segfaults for whatever input. Thanks Vincent von Schelm for bringing this to my attention!
• raising a warning about potential errors in free energy computation when using macrostate and energy parameters that violate the assumption that dl_energy + dr_energy == ext_mismatch_energy (this was true for Turner1999, but is no longer in Turner2004). See: #26
• using a non deprecated method for number rounding, thus preventing multiple warnings to bug the user in front ends
• raising a warning about potentially wrong energy computation if a) in alignment mode and b) in window mode. See: jlab/gapc#79