exception handling in _get_flag and documentation update

…ase-python-2-6-compatible-sdk

Make all code Python2.6 compatible. Add documentation, package manager support.

…)_PROXY` values

When determining if a proxy should be used, the SDK would:

1. Check the `config.http_config.http_proxy` value. If that is set, use
   that value without further consideration.
2. If the target URI is `https`, use the value from the `HTTPS_PROXY`
   environment variable.
3. If the target is `http`, use `HTTP_PROXY` instead.

The SDK will now support another environment variable -- `NO_PROXY`.
This variable can be set to a comma-separated list of hosts to exclude
from proxy support, or the special case '*' meaning to ignore all hosts.

The `NO_PROXY` variable will only take affect if the SDK isn't
explicitly configured to use a proxy as specified in #1 above.

…)_PROXY` values

When determining if a proxy should be used, the SDK would:

1. Check the `config.http_config.http_proxy` value. If that is set, use
   that value without further consideration.
2. If the target URI is `https`, use the value from the `HTTPS_PROXY`
   environment variable.
3. If the target is `http`, use `HTTP_PROXY` instead.

The SDK will now support another environment variable -- `NO_PROXY`.
This variable can be set to a comma-separated list of hosts to exclude
from proxy support, or the special case '*' meaning to ignore all hosts.

The `NO_PROXY` variable will only take affect if the SDK isn't
explicitly configured to use a proxy as specified in #1 above.

…)_PROXY` values

When determining if a proxy should be used, the SDK would:

1. Check the `config.http_config.http_proxy` value. If that is set, use
   that value without further consideration.
2. If the target URI is `https`, use the value from the `HTTPS_PROXY`
   environment variable.
3. If the target is `http`, use `HTTP_PROXY` instead.

The SDK will now support another environment variable -- `NO_PROXY`.
This variable can be set to a comma-separated list of hosts to exclude
from proxy support, or the special case '*' meaning to ignore all hosts.

The `NO_PROXY` variable will only take affect if the SDK isn't
explicitly configured to use a proxy as specified in #1 above.

…)_PROXY` values

When determining if a proxy should be used, the SDK would:

1. Check the `config.http_config.http_proxy` value. If that is set, use
   that value without further consideration.
2. If the target URI is `https`, use the value from the `HTTPS_PROXY`
   environment variable.
3. If the target is `http`, use `HTTP_PROXY` instead.

The SDK will now support another environment variable -- `NO_PROXY`.
This variable can be set to a comma-separated list of hosts to exclude
from proxy support, or the special case '*' meaning to ignore all hosts.

The `NO_PROXY` variable will only take affect if the SDK isn't
explicitly configured to use a proxy as specified in #1 above.

…)_PROXY` values (#301)

When determining if a proxy should be used, the SDK would:

1. Check the `config.http_config.http_proxy` value. If that is set, use
   that value without further consideration.
2. If the target URI is `https`, use the value from the `HTTPS_PROXY`
   environment variable.
3. If the target is `http`, use `HTTP_PROXY` instead.

The SDK will now support another environment variable -- `NO_PROXY`.
This variable can be set to a comma-separated list of hosts to exclude
from proxy support, or the special case '*' meaning to ignore all hosts.

The `NO_PROXY` variable will only take affect if the SDK isn't
explicitly configured to use a proxy as specified in #1 above.