Add missing domainrank.txt

This file was previously generated from the Alexa top-1-million
list of domains. As that list seems to be no longer available
from Alexa, I have added this file to the repository.
Updated howto.html
Fixed several compile-errors with FPC on Linux
More changes to compile with FPC on Linux
Fixed a build-error with Delphi

This error was introduced by a change made for FPC on Linux.
Reorganized the build-script for Linux
Begin porting RobotNew to FPC-Linux
Make DNSResolver compile on FPC-Linux

Note: This code compiles, but is otherwise completely untested!!!
Made MemoryFile.pas compile with FPC-Linux

Warning: Untested!!!
Should work though, as the changes were minor.
Began work to port SearchServer to FPC-Linux
Added a commandline version of SearchServer

searchservernew.dpr was created from ServerMain.pas and is
still completely untested!
Make this branch compile with Delphi XE2 again
Changes to compile with FPC/Linux

FPC/Linux code is still completely untested!!!
Fixes path-separators on Linux

Also added some more files to .gitignore which are created
when actually running the software.

Fixed date in GlobalTypes.pas and changed version to 5.0.1.
Added missing file BlockedExtensions.txt

I have no idea how I could have missed this one... sorry!
Fix a bug with file-permissions on Linux

For some reason on Linux a file named "db2.url0" gets created with
execute-only permission. It needs to be read/write.

This workaround changes the file-permissions after the file gets
closed.

I don't know if this is something that I just don't understand
about Linux, or if this could be a bug in FreePascal?
Merge branch 'fpc-linux' of https://github.com/MichaelSchoebel/OpenAcoon into fpc-linux