Add analyzer specs

Issue #5 

Summary
---
* Decoupled `ObjectSpace` from `Analyzer` via `Memtf::Analyzer::Memory`
* Added specs for the public `Analyzer` methods

Specs
---
```
Finished in 1.32 seconds
35 examples, 0 failures
```

Documentation
---
```
Files:           9
Modules:         3 (    0 undocumented)
Classes:         5 (    0 undocumented)
Constants:       7 (    0 undocumented)
Methods:        18 (    0 undocumented)
 100.00% documented
```