Some fixes and improvments

Added new features:
Fixes:

• now generates a png image for each PDF page.
• stay on Saved Games folder for users with DCS.beta.
  Added:
  Get aircraft name (from DCS folder) and current date-time and fill in the fields AIRCRAFT_NAME and PRINT_DATE (both fields must exists on template).
  Default name for output files with aircraft name and date in filename, but can be edited.
  Support for buttons with modifier (only 1 modifier). The fields must be named with "MOD-" prefix along the base name (ex.: MOD-JOY_BTN10). Suggestion: set another font color in those fields on template.

Jar file with embedded lib to run alone.