Merge pull request #1 from bdunlap/private-apps

Private app support for your shopify lib. TODO: style fixes
Last pull request cleanup: Removed the need for a code comment, made some code convention fixes and updated readme with private application details.
**Backward Incompatible Changes**
Replaced constants SHOPIFY_APP_SHARED_SECRET and SHOPIFY_PRIVATE_APP_PASSWORD with a single constant SHOPIFY_APP_SECRET.
Removed the $private_app parameter and instead introduced the constant SHOPIFY_PRIVATE_APP.
Removed ShopifyInvalidMethodException cause the API will throw an error in anycase.
Reorganized code to avoid passing parameters too deep.
Internal refactoring for clarity.
Updated readme with API call limit helper examples.
readme update: multi-paradigm FTW!
Readme download instruction fix
Readme fix about when exceptions are throw
**Backward Incompatible Changes**
Removed dependency on global constants and instead expecting those values as function parameters now.
Renamed shopify_app_installed() to shopify_is_app_installed()
**Backward Incompatible Changes**
Renamed headers to response_headers where appropriate. The only external interface change is in ShopifyApiException->getInfo() where a key in the returned hash was renamed from headers to response_headers.
readme changes suggested by @bdunlap
Bugfix suggested by colin to disable cURL's default 100-continue expectation (https://groups.google.com/group/shopify-api/msg/312bddc43b6404c3)
Added requirements to README
rename to basecamp.php
first-pass of adjustments to operate with new Basecamp
adjust copyright statement to limit it to unaltered portions of Sandeep's code
fix a couple of typo bugs, add some logging, clarify some logging
pass credentials via basic-auth and always set request headers (whether our method is GET or otherwise)
rewrite for new client.
whitespace changes in sample code.
fill out create-new-project example
Added Zend Framework compatible Path, adjustet Readme slightly