pe: pe_rva_to_offset: Round to File Alignment
pe: pe_rva_to_offset: Round to File Alignment

Closes #424

mgoffin/yara,msuvajac/yara,kallanreed/yara,tanium/yara,wxsBSD/yara,wxsBSD/yara,plusvic/yara,hillu/yara,jpypi/yara,bmagistro/yara,VirusTotal/yara,msuvajac/yara,VirusTotal/yara,cblichmann/yara,mgoffin/yara,tanium/yara,cblichmann/yara,pombredanne/yara,rednaga/yara,wxsBSD/yara,pombredanne/yara,VirusTotal/yara,pombredanne/yara,wxsBSD/yara,rednaga/yara,cblichmann/yara,hillu/yara,plusvic/yara,pombredanne/yara,mgoffin/yara,cblichmann/yara,MeteorAdminz/yara,VirusTotal/yara,plusvic/yara,kallanreed/yara,jpypi/yara,kallanreed/yara,plusvic/yara,bmagistro/yara,pombredanne/yara,jpypi/yara,rednaga/yara,MeteorAdminz/yara,msuvajac/yara,mgoffin/yara,MeteorAdminz/yara,plusvic/yara,bmagistro/yara,cblichmann/yara,hillu/yara,hillu/yara,VirusTotal/yara,hillu/yara,wxsBSD/yara,tanium/yara