I am not familiar with this saying. However, my impression is that it means that the only use for pigs is for human food, i.e. the only reason they are useful is so that humans can eat them. Hope this helps

1. The economy has held up better than many feared. 2. The British economy is better than many people thought. The British economy is better than many people feared. In these examples, "than" is a subordinate conjunction not a preposition, so it joins two sentences. There is no need for "what," which is a relative pronoun. For example, "I saw what he did." I can't think of any time when you would use "than what." Also, as an aside, "to think worried" or "thought worried" is not an English expression. Good question!

http://www.gocomics.com/explore/comics

Overall very good, mainly just a few misplaced articles. and species with of which 18% are on the list listed in Appendix I and II of the Convention on categories I and II without government permits and are criminal offenses may be traded and kept when these birds are

I have never heard the expression before, but Merriam Webster says that it means a person's best clothes. http://www.merriam-webster.com/dictionary/glad%20rags

I will try to answer this one, but I am not an accountant, and it is a little complicated. Suppose that your job entitles you to a pension. However, you only get the pension if you work five years. If you don't work at least five years for the company, then you get nothing. After five years, your pension "vests," in other words, you have possession of it and will get it when you retire. The word is also used in the context of stock options. If you get a stock option, you have a chance to buy stock at some point in the future. You might be promised stock options at the end of every year, for example. However, you can't buy the stock until the option "vests" at the end of the year, and if you leave the company before the option is "vested," then you don't get it. Basically, it can apply to the moment you take ownership of almost any kind of property. That's my best understanding of the word. I hope that helps.

In this context, you would say "My birthday is just another day for me." This means that it is an ordinary day and not a special day. "Any day" would be used differently in a number of different ways. If you said, for example, "Today is not just any day, it is my birthday," that would mean that your birthday was special. However, you could say also, "Today is not just another day . . . ." But you would not generally say "it is just any day." So, no, they are not interchangeable.

In America, we would say, "Can you help me set the table?" or "Would you please help me set the table?" Likewise, we could say, "Can you help me clear the table?" or "Would you please help me clear the table?" We would never say "lay the table" in America. But Zach's explanation above is equally good, and clearly reflects the British perspective.