Fix PKGBUILD syntax

• Fix license names with decimals (closes: #12 (closed))
• Fix parentheses in optdepends (closes: #6 (closed), #10 (closed))
• Clean up shell statements
  • Remove kornshell statement keywords
  • Remove obsolete bashStatement override
• Add more valid archs & matches (related: #7)
  • pkgname=(gdb gdb-common) is still an error