Add option to disable built-in logging

This change adds the option to specify 'none' for log_dir config value.
The effect is to disable the build-in log management in ChicagoBoss,
allowing your to drop in your own error_logger based logging system
instead.
Add compiler_options config value

This allows the user to pass extra compiler options (for example
debug_info) into ChicagoBoss's compiler.
Merge pull request #162 from bernardd/compiler_options

Add compiler_options config value
Fix test_* rebar tasks in 0.8:

starting mimetypes app in boss.erl->ensure_started(mimetypes):
 - For tests rebar-tasks, adding adding deps/*/ebin to code load
   don't work on boss.erl->ensure_started(mimetypes)

Was broken since https://github.com/evanmiller/ChicagoBoss/commit/3169166406fae1bab9a7fb5c9363c9f8615b9944#L0R22
Merge pull request #163 from jgordor/master

Fix test_* rebar tasks in 0.8
Add log_enable configuration option

This option allows the generation of log files to be disabled.
Merge pull request #161 from bernardd/master

Add option to disable built-in log management
Added extra_vmargs: A string of additional vm args that will be appended to the start* commands
Merge remote-tracking branch 'upstream/master'
Renamed extra_vmargs to vm_args (consistency)
Merge pull request #164 from jgordor/master

Added vm_args
Option to enable db_cache:

- Now you can have sessions on cache (memcached) but avoid using
cache in boss_db
Updated api-config doc-src with the new option
Merge pull request #167 from jgordor/master

Option to enable/disable boss_db cache
db_cache_enable: slight fix-up
db_cache_enable: another stylistic tweak
New "_vars" template variable contains all vars
Update skel/boss.config
Merge pull request #170 from kotedo/patch-2

Update skel/boss.config
fix crash unknow websocket services