Remove remnant Autotools files.
Revert "Fix warning: unused variable when HPP_DEBUG is unedfined."

  * This reverts commit 27f9919c8abe8274f2f719eb5c8a64ead6990057.
  * Runtime errors exceptions should be thrown here instead of
    asserts, so that the parsing stops even in release mode.
Remove and throw runtime errors in parser.