Log Message:
Update to 1.20.0:

MATE Terminal now supports background images, adds Solarized themes and \ 
keybindings to switch tabs.

Full changelog:

require VTE 0.46
screen: stop setting TERM and COLORTERM environment variables
schema: fix summary and description of some keys
remove “…” from Find keyboard shortcut
profile-editor: properly initialize the first palette color
terminal-screen.c: drop unused variables
Fix build warnings: ignoring return value of chdir,
middle click on a tab: add the gsettings key to enable the feature
make indent more uniform in a few files
fix possible crash when handling DBus method call
Spelling: Whitespace removed, in the terminal, Ctrl
add Solarized themes from gnome-terminal
WidthOfScreen and HeightOfScreen implementation
add the ability to switch tabs using ctrl + tab and ctrl + shift + tab
allow remapping “search” keyboard shortcuts
Support background images with VTE3
find-dialog.ui: fix keyboard selection
avoid deprecated vte_terminal_search_get_gregex
add “select all” keyboard shortcut: control + shift + A
gtk 3.22: avoid deprecated gdk_screen_get_monitor functions:
avoid deprecated gdk_screen_get_width/height
avoid deprecated gdk_screen_make_display_name
terminal-util: avoid deprecated gtk_show_uri
avoid deprecated gdk_display_get_screen
avoid deprecated gdk_screen_get_number
Fix: Double click with right button causes Xorg to crash
Translations update