[fpc-pascal] Google APIs

[Michael Van Canneyt]

Hello,

Some of you may have noticed that a package 'Google APis' has been added to FPC in subversion.
These contain the Google APIs as generated from the Google Discovery Service (~70 APIS).

I am of the opinion that such Web APIs have meanwhile the same importance as the native APIS 
that make up the desktop; the world is increasingly connected to Internet, and Google, MS Office365 
apis (and many others) will become more and more part of the toolset of a programmer.

Object Pascal Programmers should not be left behind.

Mattias Gaertner kindly gave permission to add a package to the 'components' directory of  Lazarus.
It will register the Google API components on the component palette (it uses the images provided by 
Google itself)

Many of the APIS will probably not be used by most programmers, but some of the core APIs will be useful for a lot of people:

Google Calendar, Google Drive, Google Tasks, Google Mail, Blogger, Youtube etc.

There are already 4 example programs in the package directory, I will add more as time permits
(Google Mail and Translate are definitely on my list).

Note: you will need to create OAuth client ID and secret keys to make them work.

The components as committed to Lazarus SVN will compile out of the box with FPC 3.1.

The components can also be compiled with FPC 2.6.4 (in fact they were developed with FPC 2.6.4)
but then some extra files must be copied from the FPC 3.1 repository to the components dir in lazarus.
(I will commit instructions for this later on)

One of the design goals was to be able to use the various TCP/IP implementations for FPC;
FPC 2.6.4 will only work with Synapse, but since 3.1 contains support for the HTTPS protocol, 
TFPHTTPClient can be used in 3.1.

Some of the components have been used in some private projects, so they work, but I would welcome experiences,
suggestions for improvement, comments.

One thing which I still plan to do is to adapt the code generator so it also creates fpdoc documentation.
(the code generator is committed to SVN)

If I broke something in the lazarus SVN or forgot a file (always an option ;) ) please let me know and I 
will fix it ASAP. But if you don't install the package, there should be no side effects to the commit.

For those of you that read Blaise Pascal magazine: the Google APIs will be featured in the next issue
(issue 41 for the English version).

As usual, comments, suggestions and contributions welcome.

Michael.

PS. The REST API for MS Office365 is next.