[nemo-qml-plugin-contacts] Do not decompose alphabetic characters

When decomposing characters to create search strings, do not decompose
characters which are members of the locale alphabet in their canonical
form.  These should not match against base characters, when searching
from that locale.
[nemo-qml-plugin-contacts] Allow search for number with initial plus

If a contact contains a number that begins with '+', allow it to be
found by searching with or without the plus character.
Fix testing of email addresses

Email address domains are no longer indexed.
[nemo-qml-plugin-contacts] Test multiple search words

Matches must match each word in the sequence.
[nemo-qml-plugin-contacts] Handle basic-latin fallback for extended latin chars

For latin chars that do not decompose into a sequence starting with
an ASCII char, create search items for transliterated versions.
[nemo-qml-plugin-contacts] Remove duplication in indexed search tokens
Merge pull request #87 from matthewvogt/search-improvements

Search improvements