Fixes to win32 (un)installation process

Updated the style of ossec-installer.nsi so it is easier to read.

Turned on Uninstallation details same as is done for installtion
details.

Start to use SimpleSC plugin (Rainer Döpke) to handle the intial
stopping of the OSSEC agent service. The hope is this plugin can later
be used to do handle all of the necessary service configuration that
is required.

Added error checking around many of the (un)installation steps. There
is plenty of room for more error checking but hopefully this covers
some of the major problem areas.

Added logic to create the ossec.log on every installation.

Fixed cleaning up the bookmarks directory.

Start to use nsProcess plugin (Shengalts Aleksander aka Instructor) to
detect if either manage_agents.exe or win32ui.exe are running during
an uninstall. When they are running the uninstallation will fail to
remove those files and thus fails to remove the ossec-agent directory.
Merge pull request #159 from awiddersheim/fix_win32_install_uninstall

Fixes to win32 (un)installation process
Moving ossec-lua back to posix so that we do no have a libreadline dep
Merge pull request #175 from jrossi/ossec-lua_remove_readline_requirements

Moving ossec-lua back to posix so that we do not have a libreadline dep
This change is for Linux
Fix windows agents compile error and warnings #define ENOBUFS, #define ALERT_SYSTEM_ERR
Merge pull request #176 from jbcheng/master

Fix windows agent compile error/warnings #define ENOBUFS, ALERT_SYSTEM_ERR
Fixes to win32 installation

Added local_internal_options.conf to the installation process. This
file will not be overwritten when an upgrade occurs so changes to how
the agent runs can be made in this file and persist through upgrades.
This fixes #169.

Also, some small fixes like removing whitespace and making the message
box definitions in ossec-installer.nsi a bit more readable.
Use the evironment for the CC binary
Merge pull request #179 from awiddersheim/fix_win32_local_internal_conf

Fixes to win32 installation
Merge pull request #180 from jrossi/fix-clang-gcc-and-lua-compile-freebsd

Use the environment for the CC binary (instead of setting CC=gcc in Makefile, be flexible for clang and others)
[tests] create make target for coverage report

* ignore and delete (on make clean) all coverage related files
* do not make libs, cause they are directly compiled into the test binaries for coverage report
[os_xml] harmonize error messages
[os_xml] refactor name of variable attribute
[os_xml] limit output in overflow error message
[os_xml] add testcases
[os_xml] refactor max size of variables
[os_xml] refactor type of xml element as enum
[os_xml] fail on too long variable names and on null-content right away
[os_xml] fill error line in ApplyVariables()
[os_xml] do not copy strings in ApplyVariables