Compatibility Step 2

Today I deployed an update to the interpreter with two fixes for incomptibilities.

1. Variables. You are no longer limited to single letter variable names. Yay! As of today Quite BASIC variables are composed by a letter optionally followed by digits. Also, dollar sign is now allowed to be appended. Quite BASIC variables are not typed, so the dollar sign has no menaing, but is is allowed for backwards compatibility. Example variable names: A, A1, A47, A$, A5$.
2. Shortcut for GOTO commands in conditionals. As of today, there is no need to type the GOTO keyword for a simple jump in an IF command. Example: "IF A=B THEN 200 ELSE 300".

I updated the doc at Club Quite BASIC to reflect these fixes.

Next up are DATA/READ commands and the semicolon delimiter. If you have feedback on which incompatibilities are more important, feel free to drop a message at feedback@quitebasic.com or in the comments here.