Fixing Compile and Data Set errors

1. First two characters of the first line of "verblist.txt" are not
separated by \t

2. "naturalsegment" method in SentenceAnalyzer.cs contains a big
switch/case. There are a lot of variables with the same name
"prefixindex" in every case which causes multiple declarations. Case
scopes should be defined by braces.
Merge pull request #3 from elnazsh/master

Fixing Compile and Data Set errors