New features for PDF and Excel formats

PDF:
- Support for logo image on top of PDF
- Changed header row to black background and white font

Excel:
- New parameter for column autosize
- New parameter for Zebra Style on rows and header
- New parameter for titles at the top of the document
Changed the version to 1.5
Merge pull request #3 from arturoojeda/master

Merged. Thanks @arturoojeda