Documentation Update

[Calum McConnell <calumlikesapplepie gmail com>]

Hello, my name is Calum McConnell, and I am interested in updating the documentation of Dia.  Its worth mentioning that this is my first 'large' open source project, but not my first time writing a large body of code.

I have taken a look through some of the more recent mailing list posts, and it seems that we are currently working through a modernization of Dia following years of no releases.  The last time the developer documentation pages like "Roadmap" were updated was in 2013, and it's probably safe to assume that they are a wee bit out of date.

So, a few questions:

1: what is the status of the GTK+ 2-3 transition?  Is it building? Does it need testing?  Are features absent, and which ones?
2: What is the status of the Windows installer? Do we need someone to take charge of that before we are prepared for the next release?

3: What is the plan for the next release? Are we pushing one out as soon as we can get a stable build? Are there already development builds available? Are we just trying to improve the codebase, without a plan for the next release?  What on earth are we calling it?

4: I saw some mention of other problems.  For instance, some of the objects use PNG files instead of SVG.  Is this still an issue?

5: The guidelines (https://wiki.gnome.org/Apps/Dia/CodingGuidelines) mentioned on the site (also edited in 2013) discuss being based off of Java style guides.  Are these the guidelines we are following as we seek to renovate?  Is there some other style guide? Or is the code too spaghettied to even worry about a formal guide?

6: The documentation refers to the code being built in C, but the github breakdown has a small amount of some other languages as well, like C++.  Is there a transition going on to C++, or is this an abandoned project?  

7: What other features have been added or changed since 2011? Or should I start reading read 8 years of commits, merges, and mail?