From the Bitcoin Core 0.10.0 release notes:
Standard script rules relaxed for P2SH addresses
The IsStandard() rules have been almost completely removed for P2SH redemption scripts, allowing applications to make use of any valid script type, such as "n-of-m OR y", hash-locked oracle addresses, etc. While the Bitcoin protocol has always supported these types of script, actually using them on mainnet has been previously inconvenient as standard Bitcoin Core nodes wouldn't relay them to miners, nor would most miners include them in blocks they mined.
So essentially the core software will now relay more intricate P2SH Txns which would previously be deemed non-standards transactions.
What are the specific changes which have been made (ie relaxed standards)? Does it only apply to P2SH Txns? Finally,
"n-of-m OR y" and
hash-locked oracle addresses are mentioned as examples: what does this refer to exactly?