added the variable  to the built-in variables
added  variable test case
1 Extract the api of nginx for compiling dso module.

2 Remove the dependence of nginx source, when compile the dso module.
Merge pull request #350 from flygoast/master

added the variable 'time_http' to the built-in variables
Merge pull request #351 from monadbobo/dso_fix1205

Enhanced the DSO module
support recording request time in usec for subrequest
Merge pull request #353 from jinglong/ali

support recording request time in usec for subrequest
add expires_by_types wildcard type support
e.g. expires_by_types 10y image/*;
Merge pull request #356 from zhcn381/upstream

add expires_by_types wildcard type support
Added variable full_request
Added escape_uri_ variable
Merge pull request #361 from yzprofile/dev

Added variable full_request & Added escape_uri_ variable
Merge branch 'master', remote-tracking branch 'upstream/master'