compile debug print functionality only when DEBUG is defined
fixed test file path in README

fa377cc9422e78570376347a94cc1147807c51e3 moved the test file from `src`
to `test`, while README still mentioned former
Merge pull request #21 from dnet/ifdef-debug-functions

compile debug print functionality only when DEBUG is defined
Merge pull request #22 from dnet/readme-test-erl

fixed test file path in README
Added add_columns_sql

Need to add columns to table.
Add sqlite3:add_columns
Merge pull request #25 from maxlapshin/patch-1

sqlite3:add_columns feature
adding columns to table

calling add_column_sql in database server
Merge pull request #26 from maxlapshin/patch-1

Handle adding of columns in database process
support for encoding true/false to sqlite
Merge pull request #27 from maxlapshin/patch-1

support for encoding true/false to sqlite
use Erlang typedefs instead of hardcoded types

for example, on Linux x86_64, ErlDrvSSizeT is long, not int
replaced deprecated function driver_output_term

From erl_driver.h:

	driver_output_term() is deprecated, and scheduled for removal in
	OTP-R17. Use erl_drv_output_term() instead.