fixed the missing with invalid character for ngx_unescape_uri
added the test cases for ngx_unescape_uri
bumped version to 1.4.6
Merge pull request #243 from zhuzhaoyuan/bump-version-1.4.6

bumped version to 1.4.6
updated the feature list
Merge pull request #244 from zhuzhaoyuan/update-readme-1.4.5

updated the feature list
Merge pull request #231 from yaoweibin/fix_unescape_uri

it looks good to me