Change StringBuilder.Remove to J2N appropiate methods

[nikcio]

Originally discussed in #654

TLDR:
StringBuilder.Remove should be replaced with StringBuilder.Delete (From J2N)
StringBuilder.Remove followed by StringBuilder.Insert replaced with StringBuilder.Replace (From J2N)

Be aware that the J2N methods uses .NET semantics startIndex and length where as the Java source uses startIndex and endIndex which means the parameters doesn't match 1:1. See #654 for more information.

Note: We should be checking against the Lucene 4.8.0 or 4.8.1 source to be sure that the methods match the original Java code.

Lucene 4.8.0 source can be found here: https://github.com/apache/lucene-solr/tree/releases/lucene-solr/4.8.0/lucene
Lucene 4.8.1 source can be found here: https://github.com/apache/lucene-solr/tree/releases/lucene-solr/4.8.1/lucene