To integrate Netrc into exsiting classes:
* src/Request.h
(_userDefinedAuthConfig): New variable.
(findNetrcAuthenticator): New function.
(segment): Removed.
(setUserDefinedAuthConfig): New function.
(resolveHttpAuthConfigItem): New function.
(resolveFtpAuthConfigItem): New function.
(resolveHttpProxyAuthConfigItem): New function.
* src/HttpRequest.h
(authConfig): Removed.
(proxyAuthConfig): Removed.
(setAuthConfig): Removed.
(setProxyAuthConfig): Removed.
* src/UrlRequest.h
(getHeadResult): Added a parameter: authConfigHandle
* src/common.h
(SingletonHolder.h): New include.
* src/main.cc
(Netrc.h): New include.
(main): Removed initial values of PREF_FTP_USER,
PREF_FTP_PASSWD.
Added initial value of PREF_NETRC_PATH.
Added the initialization of netrc.
* src/AuthConfig.h: New class.
* src/prefs.h
(PREF_NETRC_PATH): New definition.
* src/HttpAuthConfig.h: Removed.
* src/Netrc.cc
(getRequiredNextToken): New function.
(skipMacdef): New function.
(parse): Rewritten.
* src/Netrc.h
(getRequiredNextToken): New function.
(skipMacdef): New function.
* src/Util.h, src/Util.cc
(getHomeDir): New function.
* src/TrackerWatcherComand.cc
(createRequestCommand): Use AuthConfig.
* src/FtpConnection.cc
(sendUser): Use Request::resolveFtpAuthConfigItem().
(sendPass): Use Request::resolveFtpAuthConfigItem().
* src/Request.cc
(findNetrcAuthenticator): New function.
(resolveHttpAuthConfigItem): New function.
(resolveFtpAuthConfigItem): New function.
(resolveHttpProxyAuthConfigItem): New function.
* src/UrlRequestInfo.cc: Use AuthConfig.
* src/HttpRequest.cc
(createRequest): Use authConfig.
(getProxyAuthString): Use authConfig.
(configure): Removed PREF_HTTP_USER, PREF_HTTP_PASSWD,
PREF_HTTP_PROXY_USER, PREF_HTTP_PROXY_PASSWD.
