Provide HTTP Request Content Body From File

- Made HTTPRequestBuilder accept body content from a specified file.
This would be helpful when making request like PUT with large data.
- getResponseBody() method added to HTTPResponse class for extracting
all response body text at once.
Merge branch 'httprequest-content-from-file' of https://github.com/asifmujteba/httpclient into asifmujteba-httprequest-content-from-file

Conflicts:
	src/main/java/org/pixmob/httpclient/HttpRequestBuilder.java
Merge branch 'asifmujteba-httprequest-content-from-file'