FMSLogo Code

Merge in changes from trunk to get GNU/Linux implementation of SHELL

Enable a buggy version of SHELL on GNU/Linux
However buggy, this unblocks test development on GNU/Linux where functionality lacking in FMSLogo can be provided by Perl.

Change references from localizedstrings-XX.h to localizedstrings-XX.txt.
The .h file is now generated from the .txt file and is no longer given to translators.

Fix typo: "a native Spanish speaker of Spanish" -> "a native Spanish speaker"

Fix typo: "etc" -> "etc."

Update the translation instructions for the Unicode FMSLogo (version 8.0 and up)
This is mostly stating the character encoding requirements of each file.

Add CSS to not wrap <code> tags.
This improves readability by preventing filenames with hyphens from being broken across lines.

Fix a typo in the instructions for startup-XXXX.logoscript.

Refactoring: Rename some local variables to make the code more readable.

Refactoring: Extract a subroutine to write a variable to both internationalizedstrings.h and localizedstrings.cpp.
This keeps the type and name in-sync in both files.
It also make it easier to put special characters into string literals, since they can be put into a single-quoted Perl literal.