Fixed some bugs which caused some context to be not recognized, and some

Fixed some bugs which caused some context to be not recognized, and some
spurious context to be recognized.  In particular, the bugs fixed are:

1. Failure to recognize INPUT element at the end, e.g., if the input has
   the form "Item number:%S", then the pattern was recognized as only
   "Item number".

2. Failure to remove matching <foo></foo> tags if the pattern contains
   INPUT or TMPL_VAR; e.g., if the input has the form "<h1>%s %s</h1>",
   the form would not be simplified to "%s %s".

Unfortunately, fixing these 2 bugs will cause about 40 fuzzies to appear.