Bump version number to 0.14b

Bump version number to 0.14a

Bump version number to 0.14

Fix TWBT file replacement handling (fixes Pidgeot#159)

Bump version number to 0.13b

Bump version number to 0.13a

Bump version number to 0.13

Bump version number to 0.12c

Bump version number to 0.12b

Bump version number to 0.12a

Update credits in about dialog

Bump version number to 0.12