Add drupal core search support for CRM entities

@kevee, thanks for a great patch! I appreciate your help. Looks like it is working very nice for contacts! Here is my review:

• When enabling search for a CRM Core Activity following exception is thrown:

  ( ! ) Fatal error: Call to undefined function crm_core_activity_view() in /var/www/crm/dev3/profiles/drupalcrmdev/modules/crmdev/crm/modules/crm_core_activity/crm_core_activity.module on line 207
  

  This is because crm_core_activity_view() is declared in crm_core_activity_ui. I think, that it is a design flaw and we need to move crm_core_activity_view() to crm_core_activity module.

• We would like to alter fields to hide their labels, when search indexing is performed, like it is done in node module, see http://drupalcode.org/project/drupal.git/blob/refs/heads/7.x:/modules/no.... Otherwise when performing a search for Surname we will have all Individual contact types.
• Here is some empty spaces at the end of lines at the patch, but it is a minor thing.

P.S.
In a future work on a search we could also add some conditions (e.g. entity type, etc).

Yeah, it needs work now.

I am working on this patch.

After I have moved crm_core_activity_view() into crm_core_activity module, i've fund that activity search is not working, because of the drupal bug: #1425622: Increase length of 'type' field in search_dataset, search_index tables from 16 to 64.

After I have fixed drupal search bug, activity was still not working cause of the call to the crm_core_activity_type_get_name() which does not exist yet, we need to use crm_core_activity_type_name() instaead.

This patch was updated and committed, code will appear soon in the public repo.

However we need to reprove search abilities, which requires crm_core changes. What can be improved:

- ability to search in the entity tiles
- disable theme before rendering as it is done in node module: http://drupalcode.org/project/drupal.git/blob/refs/heads/7.x:/modules/no...
- ability to disable field labels from indexing

I am going to create separate issue for that.

AFAIK the search integration is actually not complete before those issues are fixed. So I think this issue should remain open to track that down, otherwise people will have a harder time finding out what needs to be done. Do we have links for them already?

Yeah, this issue depends on #1425622: Increase length of 'type' field in search_dataset, search_index tables from 16 to 64. I am updating status of this issue, cause there is nothing to do yet.