Allow closing of notifications by clicking on them

Adds a DoClick functions to notification icons made by notification/AddLegacy which changes the time left to display on the notification panel. Useful for when notifications might overlap GUI which is needs to be read or clicked on, but the entire panel is not clickable, which makes you less prone to accidentally close the panel.
Example: http://gyazo.com/15ebbcf7c769a127eee247ad49719c35.gif
Added SetMaterial to DImageButton

from DImage
Materials are now cached again

with DImageButton's inclusion of SetMaterial this now will work
SetMaterial updated
prevent player getting killed if spawnpoint is too close to world origin
string.Trim, TrimLeft, TrimRight optimizations

And removed a few stray characters in string.Explode & Replace
Removed effects.halo.Add for good.
Halo module improvements

Fixes the rendering of some brush-based entities causing the screen to
turn black. They're still a little iffy aesthetics wise, but they work.

Optimised a tad, it's 2fast now.

The visual output for props should be identical to before.
Update gmod_camera.lua

Fixed Facepunch/garrysmod-issues/issues/1389 and cleaned up the code
Fixed multiple line breaks in a row not appearing properly

A small mistake that made multiple line breaks in a row (for example "\n\n\n") not appear properly.
Merge pull request #777 from Divran/patch-3

Fixed multiple line breaks in a row not appearing properly
Update widget.lua

Prevents a stupid error from happening
Update nocollide.lua

Prevents a stupid error from happening
Merge pull request #778 from Leystryku/master

Prevented 2 errors from happening
Update constraint.lua

Fix rope exploit by blacklisting all materials with "spritecard shader".
Fix some typos where "constraint" should be "Constraint".
Cleaned up the file
Merge pull request #617 from OzymandiasLlewellyn/patch-1

Allow closing of notifications by clicking on them
Merge pull request #747 from Bo98/remove-effects.halo

Removed effects.halo.Add for good
Changed base scoreboard player line colors

Match the text color to the button color in base scoreboard
Added weapon to the properties hover halo

For NPCs and entities that have them.
Added Panel.PaintingDragging

Added Panel.PaintingDragging to be true when we are paining a panel inside drag'n'drop.