sakura: Update to 3.7.0

Changes:

* Fixed bug with fore&back colors caused by changes in rev.5...
* Merged with translations branch
* Update translation template
* Remove previously added set_style_css function.
* Reorganize the big mess of code: order functions and callb...
* Bug #1828091 fixed: sakura keeps blinking after BEL is rec...
* Added helper function to set CSS style
* Bug #1485360 fixed: bright colors broken
* Bug #1833845 fixed: make 'configuration modified' dialog o...
* Bug #1810332 fixed: unable to set 100% opacity
* Bug #1839505 fixed: block cursor doesn't reverse text colo...
* Changed default font size
* Make tango palette default again
* Bug #1792380: Solarized light doesn't work as expected. Us...
* Removed unused variable in sakura_eof
* Bug #1790317 fixed: Crash with vte 0.54

(nia)