Use strict

Requires turning IrcUtils into an Angular service, because the global variable
trick won't work with use strict.
Reuse is still easily possible by removing the angular wrapping around it.
Merge pull request #420 from glowing-bear/use-strict

[PLS TEST] Use strict
Revert "Bufferlist design attempt"

This reverts commit 2475ad2c61cb5f835ef6ef3d4d7234ce82cb9dee.
Create dark theme by extracting theme settings from glowingbear.css

* Remove style.css as those values should be themable as well.
* Update urls in index.html to link to dark theme by default
Provide a way to change the theme in the settings

* Selected theme is dynamically loaded
* Preferred theme is stored in the settings.
* Default theme = dark
Add light theme
light-theme: darken most colors by 50% and add it to theme manager
[light theme] make the background lighter
[light theme] set highlight colour to something readable
[light theme] improve readability of default grey colours
fix: fix the notification colour again
[light theme] make default text color readable
themes: fix some base colours
style option control in light theme
fix gap between input and content
Fix bug with background color bleeding through
Create dark theme by extracting theme settings from glowingbear.css

* Remove style.css as those values should be themable as well.
* Update urls in index.html to link to dark theme by default
Provide a way to change the theme in the settings

* Selected theme is dynamically loaded
* Preferred theme is stored in the settings.
* Default theme = dark
Add light theme
light-theme: darken most colors by 50% and add it to theme manager