added disasm debugger features to remove and add functions

Resubmit of https://github.com/hrydgard/ppsspp/pull/4377 without the weird merge in there

Right click adds these two options.

Before merging consider that this uses the status bar to output failure conditions `SendMessage(GetParent(wnd), WM_DEB_SETSTATUSBARTEXT, 0, (LPARAM) statusBarTextBuff);`

Also, the math for symbol insertion is done in the view class `int newSize = curAddress - prevAddr;`. Can be moved to an `InsertSymbol` function in the symbolMap but I wrote this before I made the modifications in the symbol map. So if this is wished before the merge, just comment underneath.

I don't particularly enjoy the `char statusBarTextBuff[256];` allocations everywhere, as the magic numbers are questionable but it's used in the surrounding code, so I just used it.

Last point of discussion would be default name "u_un_%08X" for new user placed function symbols.

As always, if this isn't considered useful for the project, feel free to reject.

![image](https://f.cloud.github.com/assets/465677/1439262/a3425980-4188-11e3-9003-0775f3295d62.png)