Add config item: test_scale

To test the testcases using a small test set is a good idea.
New config item called test_scale can tell the test scale to dmtest.

new item (in config file)
:test_scale

default:
:normal

new command option:
--test-scale

Signed-off-by: Akira Hayakawa <ruby.wktk@gmail.com>
[writeboost] Remove DEBUGMODE and use $test_scale instead

Signed-off-by: Akira Hayakawa <ruby.wktk@gmail.com>
Merge pull request #29 from akiradeveloper/feature/add-config-test-scale-v2

Feature/add config test scale v2