standardise on double quotes in readme

* single quotes don't render in Chrome when markdown is translated on CRAN
Add clampmax example to projection()
Merge pull request #68 from ajdm/projection

Add clampmax example to projection()
Add nf.conv argument to clampmax to replace non-finite values
Merge branch 'clampmax' of github.com:ajdm/nat into ajdm-clampmax

* 'clampmax' of github.com:ajdm/nat:
  Add nf.conv argument to clampmax to replace non-finite values
  Update .Rbuildignore for Travis changes
Simplify axis handling in plot.neuron
Correct expected values for plot.neuron test
Merge pull request #71 from ajdm/plot.neuron

Simplify axis handling in plot.neuron
Teach read.amiramesh to handle gzipped files (via R.utils) and reinstate test
full set of tests for clampmax
nf.conv -> replace.infinite and replace Inf values with NA before max

* note that this is the intended behaviour since clampmax(1,2,Inf) should
  return 2 not Inf
Merge branch 'ajdm-clampmax'

* ajdm-clampmax:
  nf.conv -> replace.infinite and replace Inf values with NA before max
  full set of tests for clampmax
  Add nf.conv argument to clampmax to replace non-finite values
  Update .Rbuildignore for Travis changes
Merge branch 'master' of github.com:jefferis/nat

* 'master' of github.com:jefferis/nat:
  Correct expected values for plot.neuron test
  Simplify axis handling in plot.neuron
  Add clampmax example to projection()
Merge branch 'read.amiramesh_gzip' of github.com:ajdm/nat into ajdm-read.amiramesh_gzip

* 'read.amiramesh_gzip' of github.com:ajdm/nat:
  Teach read.amiramesh to handle gzipped files (via R.utils) and reinstate test
implement and test is.gzip()

* NB this is a private function in nat for now
* propose to add to nat.utils soon
Switch to nat:::is.gzip to avoid R.utils dependency

* note that use of gzfile is essential to fix #14
Merge branch 'ajdm-read.amiramesh_gzip'

* ajdm-read.amiramesh_gzip:
  Switch to nat:::is.gzip to avoid R.utils dependency
  implement and test is.gzip()
  Teach read.amiramesh to handle gzipped files (via R.utils) and reinstate test