Support FP-Growth Model

A spark.mllib provides a parallel implementation of FP-Growth which is a popular algorithm to mining frequent itemsets [1].
So, Meteos should support this model.
This model allows user to find frequent word sets from text data.

User can see word sets as a stdout of model creation.

$ cat sample_fpgrowth.txt
r z h k p
z y x w v u t s
s x o n r
x z y m t s q e
z
x z y r q t p

$ meteos model-show 525f41c6-2177-4a18-86b9-8d7aaef772a9
+-------------+--------------------------------------+
| Property | Value |
+-------------+--------------------------------------+
| created_at | 2016-12-30T05:06:23.000000 |
| description | FPGrowth Model |
| id | 525f41c6-2177-4a18-86b9-8d7aaef772a9 |
| name | fp-growth-model |
| params | eydsaW1pdHMnOiA1fQ== |
| project_id | 176a497303654197b010be673c1f1709 |
| status | available |
| stderr | |
| stdout | [u'z']:5 |
| | [u'x']:4 |
| | [u'x', u'z']:3 |
| | [u'y']:3 |
| | [u'y', u'x']:3 |
| | |
| type | FPGrowth |
| user_id | 962dac0cec144163bff890c7354a5769 |
+-------------+--------------------------------------+

[1] https://spark.apache.org/docs/1.6.3/mllib-frequent-pattern-mining.html