* Rename BaseSpider.domain_name to BaseSpider.name
This patch implements the domain_name to name change in BaseSpider class and
change all spider instantiations to use the new attribute.
* Add allowed_domains to spider
This patch implements the merging of spider.domain_name and
spider.extra_domain_names in spider.allowed_domains for offsite checking
purposes.
Note that spider.domain_name is not touched by this patch, only not used.
* Remove spider.domain_name references from scrapy.stats
* Rename domain_stats to spider_stats in MemoryStatsCollector
* Use ``spider`` instead of ``domain`` in SimpledbStatsCollector
* Rename domain_stats_history table to spider_data_history and rename domain
field to spider in MysqlStatsCollector
* Refactor genspider command
The new signature for genspider is: genspider [options] <domain_name>.
Genspider uses domain_name for spider name and for the module name.
* Remove spider.domain_name references
* Update crawl command signature <spider|url>
* docs: updated references to domain_name
* examples/experimental: use spider.name
* genspider: require <name> <domain>
* spidermanager: renamed crawl_domain to crawl_spider_name
* spiderctl: updated references of *domain* to spider
* added backward compatiblity with legacy spider's attributes
'domain_name' and 'extra_domain_names'
* added encoding aliases, configurable through a new ENCODING_ALIASES setting
* Response.encoding now returns the real encoding detected for the body
* simplified TextResponse API by removing body_encoding() and
headers_encoding() methods
* Response.encoding now tries to infer the encoding from the body always (it
was done before only on HtmlResponse and TextResponse)
* removed scrapy.utils.encoding.add_encoding_alias() function
* updated implementation of scrapy.utils.response function to reflect these API
changes
* updated documentation to reflect API changes
