Shaderblocks Dev 11: Introducing Uniforms

First of all, I'm really sorry for not updating Shaderblocks in the past three months. Due to this inconsistent update schedule, we are no longer naming our updates as Biweekly updates. Instead, we'll call them Dev updates, at least before v0.1.

Now for the changelog, this update includes:

• Uniforms
• Extended backward compatibility
• Various fixes and improvements on vector popup and autocompletion
• Fix error when all vector components are the same variable
• Fix expressions not updating after a variable is renamed or deleted

Extended backward compatibility
In the previous update, we have revamped the SBL format. Because of this, the newer Shaderblocks version is not compatible with older SBL files. It could convert and read the old format, but it was for SBL version BW9 only.
Now the converter can convert the older versions too, so you can now open your old files without resaving them in Shaderblocks Biweekly 9.

Better vector popup and autocompletion positioning
The position of vector popup and autocompletion is now clamped so it won't go outside the screen anymore.