[CB-3458] remove all_load dependency. Use force load instead

Jira issue tracker: https://issues.apache.org/jira/browse/CB-3458?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13664675#comment-13664675

all_load is bad practice and breaks other SDKs with Objective-C categories. Here is a description of the problem and why all-load is bad:
http://stackoverflow.com/questions/2906147/what-does-the-all-load-linker-flag-do