more details about Nginx
Merge pull request #34 from daamien/master

more details about Nginx
Clarify ui/README.md
Fix typo in INSTALL.md, thanks fluancefg
INSTALL.md: no need to specify new version to update extension
ui: Use ISO 8601 timestamp format.
Add pg_proctab to get some system-related stats
Git should ignore pg_proctab.o
powa_proctab_get_cpu_statdata_sample now outputs percents for CPU usage
Remove useless predicate in powa_proctab_get_cpu_statdata_sample()
Add update file for extension
Add missing indexes on pg_proctab history tables
Remove unused variable in pg_proctab.c
Get rid of pg_common.h
Fix powa_proctab_get_cpu_statdata_sample
Merge branch 'proctab' of https://github.com/frost242/powa into proctab