update http client class to version 1.90
add license header to http client class
Manually handle permanently moved redirects during bootstrap process

Following redirections is only performed for GET requests by the http
client class (which conforms to the HTTP protocol). During the
autoconfiguration process using the /.well-known/carddav, a redirect
on a PROPFIND request is needed though. cdfopen can now auto-follow
redirections of arbitrary request types, which can be used during the
bootstrap process.
autodiscovery using DNS SRV and TXT records and the /.well-known/ URI
Cleanup

 - move the discovery code to a separate class
 - move common helper functions to a separate class
 - debug functions now always print the caller function
 - autodiscovery tested to work with google.com and icloud.com
   (i.e., it is sufficient to enter "google.com" or "icloud.com" as URL)
 - simplified cdfopen() API a bit
add license info for distributed libraries
Merge remote-tracking branch 'upstream/dev'
Revert "add license header to http client class"

The license is now in a separate file.

This reverts commit ce06c2c5709ab035a871cd5a0bc332fb49353f1c.
FS#87 fix bug filling the email index when adding new contacts

 - email fields without category were not considered
 - email fields with scalar values instead of arrays were not handled correctly
LICENSE-sasl remove LICENSE-sasl file from listed files and use LF line endings
Merge pull request #3 from mstilkerich/master

Autodiscovery using DNS SRV/TXT records