Backported 253a2a4bf0c3ad7019b69709b51d89e5d219553c from plugin/3.3
Fixed issues with importing networks when the current locale uses commas as the decimal point

(cherry picked from commit 5c9138259a676d10b6c171850ff763ac1fd080e8)
Implemented proxy support for Cytoscape 3

(cherry picked from commit 95634714255c00e3d6e91562e9a70043839d09a5)