Some exceptions with solutions when I using odo

I found `odo` this week, and it awesome.

Below is some exceptions when I using types of backends(`odo version: 0.5.1, Hadoop: 2.7.3`), I try to modify the source local, finally it works, below is some notes:

**Q1**. when using `ssh`/`hdfs`: IOError: [Errno 2] No such file or directory: 'hdfs://xxx.xxx.xxx.xxx:/tmp/x.csv'
recommend install:
```
pip install paramiko
pip install pywebhdfs
```

**Q2**. after Q1 `hdfs` : IOError: [Errno 2] No such file or directory: 'hdfs://xxx.xxx.xxx.xxx:/tmp/x.csv'
modify `odo/backends/hdfs.py +31`
```
with ignoring(ImportError):
from pywebhdfs.webhdfs import PyWebHdfsClient
from pywebhdfs.errors import FileNotFound
```
to:
```
from pywebhdfs.webhdfs import PyWebHdfsClient
from pywebhdfs.errors import FileNotFound
```

**Q3**. `S3`: HostRequiredError: BotoClientError: When using SigV4, you must specify a 'host' parameter.
referer: http://docs.aws.amazon.com/zh_cn/general/latest/gr/rande.html#s3_region
modify: `odo/backends/aws.py +51`, we using `us-west-1`, add host in line 51:
```
return boto.connect_s3(aws_access_key_id, aws_secret_access_key,
host='s3-us-west-1.amazonaws.com',
anon=anon)
```
> maybe add `region` or `host` parameters when call `resource`.

**Q4**: `HDFS` backend: KeyError: 'name' --> name is first column name in csv
because hdfs pass `dshape` param when call `source.hdfs.read_file`, so, modify `odo/backends/hdfs.py +434`, remove `dshape` from `kwargs` when call `source.hdfs.read_file`.

more information:
```
# uri_without_host = 'http://{host}:50070/webhdfs/v1/tmp/y.csv?op=OPEN&user=hdfs&host=127.0.0.1&port=50070&dshape=var * {name: string, age: int64}&user.name=hdfs'
uri = uri_without_host.format(host=host) # uri_without_host include dshape which has `{}`, so it will raise exception using format
```

**Q5**: `odo` not support collections of files in `S3`/`HDFS`.
It clear in the documents http://odo.pydata.org/en/latest/uri.html , but other tools(such as spark or hive) always create lots of csv file in hdfs or s3 path, so we need it.

----

I did not modify as a patch, because I am not sure whether it is correct. Please give me some suggestions if you met the same questions.