For Windows users: Add a note about the gcc dependency to the README

[hstolte]

Hi, I just tried installing timeliner on Windows 10 and noticed that the go-sqlite3 dependency requires gcc.

On Windows, gcc is not included and has to be installed manually. Maybe you could add a note about that in the install section of the readme, as long as there will be no binaries available for download.

Using chocolatey, this installs the necessary dependencies on Windows:

choco install golang mingw

[mholt]

Good point, thanks for mentioning this!