Indentation and empty newlines in StringBuilder
More consistent key/value parsing in NpgsqlConnectionStringBuilder

.NET's DbConnectionStringBuilder, which NpgsqlConnectionStringBuilder extends,
trims strings values and discards pairs with empty ones. However, NCSB's setter
behaved differently, adding empty strings, leading to inconsistent behavior
(bug #1011001).

Modified NCSB's behavior to be consistent with DCSB - trim and discard empty.
Merge pull request #17 from roji/bug1011001

[#1011001] More consistent key/value parsing in NpgsqlConnectionStringBuilder.