* created new decoder and encoder for PFM
pfm file format stores binary RGB or grayscale float images.
* added test for pfm codec
* replaced large with short licence header
* little/big-endian-check is now compile time
* fixed width/height confusion, improved big/little endian recognition, fixed scaling issue and Improved signature check
* adapted tests to handle float images well
* removed data-dependency: lena.pfm
the lena image is now loaded is pam and converted to pfm.
* fixed bug in endianess detection macro
* Added endianess detection for android and win
* removed fancy endianess detection
endianess detection will be implemented in cmake scripts soonish.
* fixed minor warnings
* fixed stupid elif defined bug
* silenced some implicit cast warnings
* replaced std::to_string with std::stringstream solution
std::to_string variant did not build on android.
* replaced new endianess macros with existing ones
* improved readability
