Fixed problem for transaction test mode.

trans_complete function is committed in test mode.
Because any database drivers are set _trans_failure in test_mode,
And trans_complete function is not evaluate _trans_failure.
fixed for styleguide.

|| to OR
remove the empty line at EOF
Fixed for styleguide.
Add common robot user agents.
Merge pull request #2382 from garthkerr/add-bot-agents

Add common robot user agents.
Merge pull request #2343 from QOX/develop

Fixed problem for transaction test mode.
Add a changelog entry for PR #2343
Fix #2380 and deprecate CI_Router::fetch_*() methods
Fix #2387
[ci skip] Replace spaces with tabs
Replace another fetch_directory() use
Add options in create_captcha() to specify the randomly generated captcha word length and character pool

Uses the same defaults as were hard coded in (8 chars in length,
0-9a-aA-Z). Small change in this file means less code elsewhere when
generating random character strings for the captcha word.
typo change

Uses the same defaults as were hard coded in (8 chars in length,
0-9a-aA-Z). Small change in this file means less code elsewhere when
generating random character strings for the captcha word. all existing
code will work the same.
Updated documenation
documenation edit
Documentation change - explanation of captcha_word_length and character_pool_for_generated_word
removed sanity checks (developer-supplied value, not user input), added changelog entry, changed variable names
changed changelog format.
changelog change
eol test.