FMSLogo Code

Fix build break on GNU/Linux when compiling without precompiled headers

Add some comments

Fix typo: "procedures operator on" -> "procedures which operate on"

Standardize on "drawing surface" as a term («área de dibujo» in Spanish)

Fix Bug #566; Parenthesized expressions no longer interfere with parsing subexpressions with infix operators.
For example: "(POWER 1 + BITOR 1 2 4)"

Add some comments to paren_infix.

Add screenshots to the sample instructions for modifying the the desktop shortcut.

Add an explicit regression test for bug #506.

Standardize on using «píxel» (with an accent on the i) in the Spanish manual.

Reorganize the command-line options section so that all options are on the same page.
Also, move the explanation of how to configure the options in the shortcut to after the section that explains what the shortcuts are.