FIX wrong connection termination on start
NEW arbitrary per-pool start-up commands

Allow adding arbitrary post-connection start-up commands per pool. These
can be used to change state of all connections before issuing any
queries. For example, SQL_MODE, TIME_ZONE, etc.

Also add a bunch of environment tests.

Closes #43
Closes #78
Merge pull request #79 from spilgames/arbitrary_cmds

Arbitrary commands on pool startup
Merge pull request #81 from moxford/master

as_dict/1 and as_proplist/1 additions to emysql_util
This periodically test the connection with a MySQL native ping before sending a command.

This is a passive way to reconnect, without losing a query.
I manually applied Eonblast/Emysql pull request #45 to refresh the patch.
See: https://github.com/Eonblast/Emysql/pull/54
Update emysql.erl

add a guard clause to add_pool/8
Conflicts:
	src/emysql.erl
Databases can be `undefined`

The environment suite supplies an `undefined` atom as the database parameter.
Alter the code to allow for this.
Fix test cases to comply with connection checking.

@mremond introduced a patch which does periodical connection checking to
make sure Mysql connections are up and running. Alter the test cases to
take into account that `#emysql_connection{}` records now have more fields.
Merge pull request #83 from moxford/master

Changes for empty result sets
Revert "FIX wrong connection termination on start"

This reverts commit 27dc420da864a31c22288a4f677737c8a58ba6c9.
add as_json output util (#74)
better as_json output util
add basic test case for as_json util
add README hint for as_json util
Propagate connection initialization problems

When connection failed to open, it used to not tell it to the caller.
With this patch it propagates the error to the caller (like it used to
be in 0.2), and closes the orphaned connections (which is a new
feature).

This patch also makes basic tests pass again.
Travis-ci support

travis-ci requires different credentials than we have by default,
therefore a conditional for credentials in tests was introduced.
Merge pull request #90 from Motiejus/travis

Enable travis-ci
Allow passing start_cmds from environment
Merge pull request #91 from Motiejus/arbitrary_cmds2

Allow passing start_cmds from environment
NEW optionally skip encoding