1.18 Beta 1 first changes

Minor bugfixes:
duplicate entries when changing formats
the export feature wasn't writing the whole DI calendar URL when
exporting
Gallery added
1.19 Beta 1

# Added a themes viewer to quickly download and apply themes from the
onlin gallery, accessible using the Get more themes! option in the
Themes dropdown
# Now the options file will be saved after OK or Apply is used in the
Options panel
1.19 Beta 2

Per-channel equalizer and bug fixes