Fix recent instigator crashes

A collection of fixes for the following crash issues:

• wrong uses of resolve() in content handling code
• erroneous struct access when handling TW_Tqq in text extraction
• erroneous handling of clear codes in the LZW decoder

Fixes issues #25 (closed), #31 (closed), #35 (closed), #36 (closed), and #37 (closed).

Include some insignificant drive-by tweaks.