Bump minimum Test::Pod Dependency

In 47589465 we started feeding dirs to all_pod_files_ok - only Test::Pod 1.42
understands that
Require bugfixed (and a tad faster) CAG
Fix very subtle but deadly bug in single()

The _select_args result storage introduced in 975b573a did not take
into account that single() operates on the $rs itself, not a fresh
one. As such the first single() arg would be carried around and then
applied to subsequent next() etc iterations. Stop that, as we only
need the attrs in case of collapse => 1 and single() explicitly does
not support this.

While at it do not reuse the cached args at all - while it *appears*
safe, it may very well not be. Leave this for another day
Stop instantiating a cursor on single() use

This minor pessimization snuck in all the way back in 4e9fc3f3.
I am actually not entirely sure whether this isn't a bug - after
all this way Cursor::Cached and friends are bypassed. However
0.08210 has an identical behavior, thus sod it
Unbreak devrel version checks

One needs to supply the literal (string) value of a devrel to VERSION()
otherwise the checks fail. However in this case 5.8 emits annoying warnings.
Abstract the whole insanity in a neatish util function and use that.
Devrel 0.08249_04
fix syntax error in pod documentation for find_or_new
Stop adding empty caches to resultsets chained off prefetched objects

Prior to ce55688, the related_rs cache loading mechanism only conditionally
loaded if the base rs cache was defined. After this was removed an empty
arrayref (meaning "no related results") could potentially be set as the cache.
This commit ensures the cache is only set when there are actual cache results.
Do not invoke the pk accessor in filter deflate
devrel 0.08249_05
Kill intra-devrel changelog entry

The log is large enough as it is, hence keeping only things that
are relevant when upgrading from 0.08210 to current
This stuff is done (either now or earlier)
Release v0.08250
fixed xt/pod.t failure in Row.pm
Replace $row with $result in all docs

to be consistent and to clarify various return values
for example:
    $result->update() returns $result
before the example was
    $row->update() returns $result
which doesn't make clear that it's the same object the method was called on
Add header for custom coderef join conditions

The conditon docs are huge, making it hard to point people to the
coderef syntax when they need it, so add a header that can be linked
directly to.
Don't try to run pperl --kill if we didn't find PPerl

There might be an unrelated pperl binary in the user's path, so avoid
running it unless we actually have PPerl.pm installed
quick-start documentation

* ready-to-use database file and schema classes
* introduce CD year column (already used in ::ResultSet docs)
* link from main synopsis
point out where in the docs a user is most likely to spend reading time
Fix glossary link