finish implementation and cythoning of remaining basal methods

[wasade]

• preorder (note, generally using the select version right now)
• postorder (note, generally using the select version right now)
• levelnext
• levelprev
• isancestor
• subtree (note, would be useful to have a getsubtree as well)
• levelancestor
• levelleftmost
• levelrightmost
• degree
• child
• childrank
• lca
• deepestnode
• height
• mincount
• minselect

[wasade]

mincount and minselect are not optimized algorithmically, and so more aggressive cythoning has been deferred. It should be possible to leverage the binary tree for both of these operations. Impact: degree and childrank use mincount. child uses minselect

[wasade]

The following methods are deferred for implementation as they are not done yet, and not needed right now:

• levelprev (defined as levelprev(i) = open(bwdsearch(i, 0)+1))
• levelleftmost (defined as levelleftmost(d) = fwdsearch(0, d))
• levelrightmost (defined as levelrightmost(d) = open(bwdsearch(2n + 1, d)))
• degree (defined as degree(i) = mincount(i + 1, close(i) − 1))
• child (defined as child(i, q) = minselect(i+1, close(i)−1, q−1)+1 for q > 1)
• childrank (defined as childrank(i) = mincount(parent(i) + 1, i) + 1; unless B[i − 1] = 1 (in which case childrank(i) = 1))