Make it compilable under mingw

Add GPS timestamp without leap seconds equivalent

Ability to show GPS timestamps from Unix timestamps

Update license

Incremented patch ver

Incremented api version. Fixed comment headings.

Removed deprecated function calls

First version

-------------
* conversion using the selected text in the editor
* conversion using the clipboard [configurable]
* results in a popup message box [configurable]
* results in Messages window
* error messages [configurable]