Allow Interval per File block for tail plugin

The allows each <File> block in the tail plugin config to specify
its own Interval value. If ommitted, will use the default.
Add ReportByCpu and ValuesPercentage for cpu plugin

ReportByCpu defaults to true, ValuesPercentage to false

This enables the following use cases:

- ReportByCpu false: emits normalized percentage values
- ValuesPercentage true: emits percentage values
- default: send per core ticks, as previously
handle comments from @octo
fix typos
keep plugin instance for first cpu
add a value_to_rate function.
as advised by @octo move to a rate computing function
typo fixes.
Merge branch 'master' into feature-normalized-cpu
better indentation.
contrib/collection.cgi: Add license header.

Thanks for Mirko and Sebastian to agreeing to this licensing!
Merge remote-tracking branch 'github/master'
removed invalid space from macro definition
Merge remote-tracking branch 'origin/pr/524'
Graphite deals poorly with metric names containing quotes.

Sanitize graphite metrics with our own escaping function,
better suited for this use-case than the one in `utils_parse_option`
Merge pull request #525 from collectd/feature-better-graphite-escape

Graphite deals poorly with metric names containing quotes.
redis allows passwords up to 512 characters long
Fix tcp state names to be like others.
memory plugin: fix submit multivalue (fill vl.type)
HTTP Digest support for curl plugins