fix build error for VC++ 2013

fix following compilation error:
45>C:\mrnwork\powershell\work\source\include\mysql/psi/mysql_file.h(541):
error
C3861: 'fgets': identifier not found
...
Merge pull request #10 from cosmo0920/fix-build-for-vc2013

fix build error for VC++ 2013

Patch by cosmo0920. Thanks!!!
doc: remove needless note
doc install:fix quote
Merge pull request #11 from naoa/doc-centos6-scl-fix-quote

doc install:fix quote

Patch by Naoya Murakami. Thanks!!!
test: follow Groonga's syntax error message improvement
test: move no comment add column test to add column tests group
Fix a typo
test: ensure restoring the original default storage engine
test: use memory instead of disk

It is very fast!!! Wow!
test: load Mroonga plugin by default

Without this, the following error is occurred when one MySQL server runs
two tests:

    errno: 0 service 'thd_alloc_service' interface version mismatch:

The error isn't occurred when one MySQL server runs only one test.

It means that plugin load/unload is a problem. But why?
Add generic debug flags for --with-debug
storage: use white list style for supported inplace alter table
Extract long code as a method
travis: use Groonga at master
storage:support inplace alter table for add/drop column refs #2277
storage:support inplace alter table for alter column order refs #2277
storage:support inplace alter table for alter column rename refs #2277
Merge pull request #12 from naoa/inplace-alter-table-column

support Inplace alter table for add/drop column

Patch by Naoya Murakami. Thanks!!!
test: use meaningful test case name

"rename" is duplicated.