Changed nfdump_str
Fix network and ceilometer plugin

- Fix remote commands for nfdump
- Change error to warning in ceilometer plugin
Fix network plugin

- Remove stderr.read() from nf_dump command execte. It just hanging plugin.
Change default date in pricing_statistics to yesterday

- Change default date in pricing_statistics to yesterday
Merge pull request #145 from kula1922/hotfix/fix-network-collect-plugin

Hotfix/fix network collect plugin
Merge pull request #146 from kula1922/hotfix/change-default-date-in-pricing-statistics

Change default date in pricing_statistics to yesterday
Update CHANGES and fix requiremenets
fixed
update travis
Merge pull request #147 from kula1922/hotfix/network

fixed
fixed network report incomplete price
report with sum of costs of usageprices fixed; tests for sum of costs of usageprices added
team percent rounding fixed
flake8
flake8 v2
rounded fixed
flake8
Merge pull request #150 from mkurek/fix/teams-percent-round

team percent rounding fixed
Merge pull request #149 from mkurek/fix/network-report-costs

Fix: report with sum of costs of usageprices