Implemented a "shortcut" to WHERE conditions by:

1.- Implementing constructor Where(Context, String)
2.- Making Where extend Condition

This way you can immediately add conditions starting with the Where itself:

List<Person> persons = new QueryBuilderHSQLDB(connection).select()
														   .all()
														   .from()
														   .table("PERSON p")
										              ----->     .where("p.name = 'Jonathan'")
														   .list(new PersonRowMapper());
Implementation of Select.columns(String... columns). 

Usage:

List<Person> persons = new QueryBuilderHSQLDB(connection).select()
                                          ---------->      .columns("p.name", "p.birthday", "p.country_id", "c.country_name")
														   .from()
														   .table("PERSON p")
														   .innerJoin("COUNTRY c ON c.id = p.country_id")
														   .list(new PersonRowMapper());
It's now possible to specify several tables in a select query and to just use the equi-join (http://en.wikipedia.org/wiki/Join_(SQL)#Equi-join) syntax which - to me - comes more natural than the INNER/OUTER/NATURAL JOIN stuff.

Usage:

List<Person> persons = new QueryBuilderHSQLDB(connection).select()
														   .columns("p.name", "p.birthday", "p.country_id", "c.country_name")
														   .from()
														   .table("PERSON p")
                               .table("country c")
                       ----->  .where("c.id = p.country_id")
														   .list(new PersonRowMapper());

List<Person> persons = new QueryBuilderHSQLDB(connection).select()
														   .columns("p.name", "p.birthday", "p.country_id", "c.country_name")
														   .from()
											 ----->  .tables("PERSON p", "COUNTRY c")
                       ----->  .where("c.id = p.country_id")
														   .list(new PersonRowMapper());
Can now specify subqueries in From, but only in literal form for now - a type-safe implementation would need more thought. :)

Usage:

List<Person> persons = new QueryBuilderHSQLDB(connection).select()
														   .columns("p.name", "p.birthday", "p.country_id", "c.country_name")
														   .from()
														   .table("PERSON p")
                       ---->   .select("select * from country", "c")
                                                           .where("c.id = p.country_id")
														   .list(new PersonRowMapper());
Merge pull request #1 from llorllale/master

A few small improvements