Merging r4036, r4055, r4056, r4057, r4058, r4059, r4060, r4061, r4062, r4063,

Merging r4036, r4055, r4056, r4057, r4058, r4059, r4060, r4061, r4062, r4063,
r4064:

Ranges related fixes:

The "max_ranges" directive.
"max_ranges 0" disables ranges support at all,
"max_ranges 1" allows the single range, etc.
By default number of ranges is unlimited, to be precise, 2^31-1.

If client requests more ranges than "max_ranges" permits,
nginx disables ranges and returns just the source response.

If total size of all ranges is greater than source response size,
then nginx disables ranges and returns just the source response.
This fix should not affect well-behaving applications but will defeat
DoS attempts exploiting malicious byte ranges.

Now unsatisfiable ranges are processed according to RFC 2616.