[iOS] Fix compiler error with booleans inside objects

[colinking]

Fixes an issue where the iOS generator would generate clients that would fail to compile if they contained a non-nullable boolean inside of an object. At a high-level:

• Nullable or optional booleans/integers generate as NSNumber * instead of BOOL * / NSInteger *. Required non-nullable booleans/integers are still BOOL/NSIntegers.
• A missing space is now added between the type and name when generating objects, except for * types, which don't include that space (f.e. BOOL foo vs. NSNumber *foo)
• Removes strong and nonnull modifiers from BOOL / NSInteger types.

For more details:

• The changes to client generation are here: 6536f33
• How that changes the generated output of the test suite is here: d1513c9

This PR also updates the test suite to test all optional, required and nullable types within an object.

RFPR of: #107